高雷诺数湍流横侧射流的大涡模拟

发布时间：2018-02-12 06:53

本文关键词： 湍流横侧射流大涡模拟反向旋转涡对马蹄涡　出处：《推进技术》2016年05期 　论文类型：期刊论文

【摘要】：采用大涡模拟(LES)方法研究横向主流与壁面射流均为高雷诺数的壁面横侧射流(JICF),采用动态Smagorinsky涡粘模型对亚格子尺度进行封闭。数值模拟结果中,近场和远场的平均速度、均方根值均与实验结果符合很好。瞬时压力等值面在射流迎风侧与射流迹线成正交关系,表明JICF近场迎风涡是由于射流出口上游剪切层Kelvin Helmholtz不稳定性引起的。基于长度尺度RD,Broadwell和Breidenthal提出了射流迹线公式,通过拟合数值模拟结果得到公式中常数A=1.35,B=0.3。采用平均流线、平均场涡量与Q准则分析三维涡旋结构。横向主流遇到射流后发生夹带现象,在射流出口下游受涡旋结构的影响发生卷起;平均涡量等值面表明,反向旋转涡对(CVP)的涡旋方向与射流出口下游马蹄涡两个分支的涡旋方向相反;由于横向主流和射流雷诺数较高,Q准则表征的涡旋结构在射流出口下游一倍射流直径位置开始发生破碎。
[Abstract]:The large eddy simulation (les) method is used to study the lateral jet with high Reynolds number, and the dynamic Smagorinsky vortex-viscosity model is used to close the sub-lattice scale. The average velocities in the near and far fields are obtained by numerical simulation. The root mean square (RMS) values agree well with the experimental results. The instantaneous pressure isosurface is orthogonal to the jet trace on the jet windward side. It is shown that the upwind vortex in the near field of JICF is caused by the instability of Kelvin Helmholtz in the upstream shear layer of jet outlet. Based on the length scale, the formula of jet trace line is proposed by Breidenthal and the formula is obtained by fitting the numerical simulation results. The mean field vorticity and Q criterion are used to analyze the three-dimensional vortex structure. The phenomenon of entrainment occurs after the transverse mainstream meets the jet, and the vortex structure is affected by the vortex structure downstream of the jet outlet, and the mean vorticity isosurface shows that, The direction of the vortex is opposite to that of the two branches of the horseshoe vortex downstream of the jet outlet. The vortex structure characterized by the transverse mainstream and jet Reynolds number higher Q criterion began to break down at the position of jet diameter doubling downstream of the jet outlet.
【作者单位】：中国科学技术大学热科学与能源工程系;
【基金】：国家自然科学基金(51176178) 国家自然科学重点基金(50936005)
【分类号】：O358

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